Philo maltby



P. MALTBY.

' (No Model.)

PIsToN.

` Patented Nov'. 13 1888.

Witwe/mm,

Unire rares PHILO MALTBY, OF CLEVELAND, OHIO, ASSIGNOR OF ONE-HALF TO L. G. IIINE, OF VASHINGTON, DISTRICT OF COLUMBIA.

PISTON.

SPECIFICATION forming part of Letters Patent No. 392,680, dated November 13'. 1888.

Application filed July 27, 1888. Serial No. 281.176. (No model.)

To @ZZ whom it may concern:

Be it known that I, PHILO MALTBY, of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain Improvements in Pistons, of which the following is a specification.

My invention relates to circular pistons which are provided with adjustable metallic packing.

. The aim ofthe invention is more particularly to provide a piston suitable for use in steamcontrolling valves, which may be readily adjusted to compensate for wear and to maintain at all times a practically circular form, and the packing of which shall be at all times securely heldin such manner that the valve may be carried to and fro across the ports without liability ot' the packing dropping or otherwise moving in such manner as to wear or cnt away the edges ofthe ports.

Valve-pistons as commonly constructed are either made without packing and without means of compensating for wear, or, on the other hand, if provided with packing of the ordinary character they are liable to wear and cut away the edges of the ports in such manner as to give the same a rounding form and thereby produce leakage. To avoid these difficulties I provide my piston with Wearing or packing rings combined with devices whereby they may be forced outward to compensate for wear and firmly secured after adjustment to prevent them from moving outward accidentally or improperly beyond the positions to which they were adjusted.

In the accompanying drawings, Figure l is a view ofa valve-rod provided with two pistons constructed on my plan, one beingshown in elevation and the other in section through its center on the line m w, Fig. 2. Fig. 2 is a face view of one of the pistons with the outer or covering plate removed. As the two pistons are constructed in duplicate,a description of one will answer also as a description of the other.

Referring to the drawings, A represents the cylinder piston-head, and B a follower-plate, both applied to the valve-rod C.

D D D are three segmental wearing or packing plates inserted between the head A and the follower-plate B. These plates are of segmental -form and of such size and so fitted that when in position they form jointly a continuous ring or bearing-surface of true circular form on the periphery. The packing or wearing sections are beveled inward at their ends and seated against the three intermediate wedges E E E. The plates are slotted in a radial direction and secured by bolts F, tapped into the head A. The wedges are so proportioned and tapered at such angle that when moved outward they carry the wearing-plates D outward from the center to practically the same distance at all points in their length. The wedges terminate at the circumference of the piston and serve to close or bridge over the space between the sections D as the parts are adjusted.

The wedges E, like the wearing-sections D, are slotted radially and secured by bolts E2, which are extended through the follower-plate B, and are provided with jam-nuts. These bolts serve the double purpose of securing the wedges and of holding the follower-plate. For the purpose of moving the wedges outward I propose to employ adjusting devices of any suitable character; butI recommend, as shown in the drawings, wedges G, seated one behind each Wedge D and against a iiat face formed on the central hub, a, of the piston. These secondary wedges G may be forced inward by means of screws Il, tapped through the follower-plate, as shown, or by any equivalent arrangement.

rlhe follower-plate may be secured in position in any suitable manner, but I prefer to continuethe bolts F by which the sections D are held through the follower-plate and to provide them on the outer ends with jam-nuts b, as shown in Fig. l. When thus constructed, each bolt serves not only to hold one of the wearing or packing sections D, but also to assist in holding the follower-plate.

The outer or protruding ends of the bolts F may be made of square form or otherwise formed to receive a wrench or tool for turning them, so that the section D may be released for adjustment without removing the followerplate.

It is to be observed as a peculiarity of my head that it presents'a solid unbroken peripheral surface to receive the wear, and that the IOO sections D are not only adj usted and held positively outward, but also positively held in place, so that they cannot move outward beyond their proper or working position. As a result of this arrangement I have a practically solid piston adapted to play to and fro across the ports without thc slightest danger of cutting or wearing their edges. Valves or pistons thus constructed may be successfully used without the necessity of providing the ports, as usual, with bridges to sustain the pistons while passing thereover.

In various forms ofsteam-engine itis necessary to employ two pistons upon a single operating-rod. In order that this may be done and that provision may be made for varying the distance between the pistons, as occasion may require, I propose to divide the rod at any suitable point between the pistons, as shown in Fig. 1, and to connect thc two parts end to end by a sleeve or collar, I, which may be threaded internally and screwed upon the threaded ends of the sections, or otherwise attached thereto to ad mit of their being adjusted longitudinally with respect to each other. One of the pistons may be fixed rigidly upon the rod. The other will beattached thereto by setscrews, as shown in Fig. l, or by equivalent fastening devices to admit of its being adjusted lengthwise of the rod. By thus providing for a change of distance between the two pistons upon the rod I am enabled to properly adjust the pistons to meet all practical requirements.

Havingthus described my invention,wl1at I claim isl. The adj ustable solid piston, Consisting ol the head A, the follower B, the radially-adjustable bearing -sections D, their movable supporting-wedges E, and bolts F, rmly securing said sections against outward movements, whereby the wearingsections are prevented from dropping into or cutting the ports as the piston passes thereover.

2. The piston-head provided with radiallyadjustable bearing or packing plates, in combination with adjustable wedges to force said plates outward, and fastening devices, substantially as shown, to prevent the sections from moving outward beyond the positions to which they are adj usted.

3. In a piston, the head Aand followerB, in combination with the intermediate radiallyadjustable bearing-sections D, and bolts F,pro vided with collars or nuts to retain said sections, and also with external nuts to retain the follower-plate.

4. In a piston, the head A and follower-plate B, in combination with the slotted radiallyadjustable metal sections D, the intermediate wedges E, the internal wedges, G, the fastening-bolts F, and adjusting-bolts H.

In testimony whereofI hereunto set my hand, this 19th day of July, 1888, in the presence of two attesting witnesses.

Witnesses:

JOHN T. ARMs, W. R. KENNEDY. 

